This invention relates to a cam arrangement for converting continuous rotational motions of an input shaft into either rocking motions or intermittent motions accompanied by vertical up and down motions of an output shaft, and more particularly to a cam arrangement which is applicable to what is known as "a pick and place" unit wherein a work placed at a predetermined position is chucked by a chucking device and is moved by a rocking or intermittent motion of the unit to a working station on various machines such as an automatic assembling machine, an automatic working machine, or the like.
Most conventional cam arrangements which are applied to pick and place units include a cam for providing a chuck mounted on the output shaft with vertical motions and another separate cam for providing either rocking or intermittent motions for the chuck. Such a dual cam structure requires a large space and is complicated due to a great number of parts involved. Another known cam arrangement includes a single cam employed to convert the rotational motions of the input shaft into both the vertical motions and the rocking or intermittent motions of the output shaft. In this cam arrangement, however, the conversion into the vertical motions is made through an arm member or the like, thus also causing an increase of the parts and volume of the device. Further, the conventional cam arrangements have difficulties in improving the working speed of the chuck by overlapping the vertical motions and the rocking or intermittent motions.